One possibility could be a story where Android 21, with her unique powers and intelligence, teams up with Goku to face a new and powerful enemy. Maybe they start off as reluctant allies, with Goku being a bit wary of Android 21's past as an android. But as they fight together, they learn to trust each other and their combined strength becomes a force to be reckoned with.
Perhaps in the fanfic, Android 21 discovers a new side to Goku. She sees his love for his family and friends and is inspired to find a similar connection. Goku, on the other hand, sees Android 21's potential for good and tries to bring out the best in her. Their relationship could be a central theme, with them growing both as individuals and as friends throughout the story.
A possible plot could be that Android 18 and Goku are thrown into an alternate dimension where they have to rely on each other to survive. In this dimension, they face challenges that test their friendship and fighting skills. Android 18 might learn some of Goku's signature moves and Goku could learn more about the technology within Android 18.
It might also be a story about self - discovery. Android 18 could be exploring her more human side with Goku's influence. Goku, on the other hand, could learn more about the androids and how they are not all just mindless killing machines. The 'lemon' aspect might imply some sort of budding relationship that is full of passion and challenges as they come from very different backgrounds.
One possible plot could be a story of Goku and Android 21 teaming up against a new and powerful enemy. They start off as reluctant allies. Goku is initially wary of Android 21 due to her being an android, but as they face challenges together, they begin to understand and respect each other's powers. They could learn new techniques from one another and in the end, become friends. This would be a great way to show their growth and the power of friendship across different species in the Dragon Ball universe.
Perhaps the fanfic could be a time - travel story. Android 21 accidentally sends Goku back in time to a point where she was first created. Goku then tries to prevent her from becoming the villain she was meant to be. This would involve Goku having to deal with the scientists who created her and convincing them to take a different path in their research, all while trying to find his way back to his own time.
A possible relationship could be a friendly rivalry. They are both powerful in their own ways. Goku is a Saiyan with incredible physical strength and combat abilities, while Android 21 has her own set of unique powers. They might constantly challenge each other to friendly spars, which would help them both improve their skills and also deepen their understanding of each other.
Unique storylines. For example, a story where Android Goku has to face an entirely new kind of threat that the regular Goku never had to deal with. It could be a technological virus that affects his android parts in a strange way.
A possible plot could be that Android 18 gets injured during a fight and Goku takes it upon himself to protect and heal her. This close proximity leads to the development of feelings, which is where the 'lemon' part might come in. Their relationship could be a secret at first as they are from different 'worlds' in a sense, with Goku being a Saiyan hero and Android 18 being an android once created for destruction.
Well, in a fanfic, Kid Goku and Android 18 could have an interesting dynamic. Kid Goku is pure - hearted and always eager for a good fight. Android 18, on the other hand, is tough and has her own sense of justice. Their interaction might start with a misunderstanding. Maybe Goku mistakes 18 for a bad guy at first because she's an android. But then, as they get to know each other, they could end up teaming up against a common enemy. Goku would be impressed by 18's strength, and 18 might be a bit amused by Goku's naivete.
Character development is key. In a good 'Goku x Android 18 fanfic', we should see both characters grow and change because of their relationship. For example, Goku might become more in - tune with his emotions, and Android 18 could become more open. Also, an interesting plot that goes beyond the typical fight - and - save - the - world scenario is great. Maybe something like them exploring a new world together or having to solve a mystery.
One plot could involve time travel. Android 1 travels back in time and meets a younger Goku. At first, Goku is suspicious of her, but as they interact more, they start to care for each other. Android 1 tries to help Goku in his battles against the Saiyans in this timeline. Their love story unfolds as they try to change the future for the better, with their relationship being a key factor in uniting different factions in the fight against greater threats.